/Engine/Source/Runtime/Core/Public/Templates/SharedPointer.h
Special constructor used internally to cast a 'const' weak pointer a 'mutable' pointer. You should never call this constructor directly. Instead, use the ConstCastWeakPtr() function. This constructor creates a weak pointer as a weak reference to an existing weak pointer after const casting that pointer's object. This constructor is needed for const casts.
template<typename OtherType> TWeakPtr ( [TWeakPtr](API\Runtime\Core\Templates\TWeakPtr)< OtherType, Mode > const & InWeakPtr, [SharedPointerInternals::FConstCastTag](API\Runtime\Core\Templates\FConstCastTag) )